Sprayable low volatility in-mold gel coat compositions

Abstract

A thermosettable in-mold exterior gel coat composition exhibiting low or no volatile organic content for use with molded plastic substrates, includes fiber reinforced substrates. The gel coat composition is composed of an ethynically unsaturated polyester resin and utilizes as a co-polymerizable reactive diluent therein an acrylate or methacrylate ester component having from 2 to 4 carbon atom alkyl substituent radicals depending thereon, coupled with a 5 to 10 carbon-atom-containing mono or dicyclic alkyl or alkenyl ester radical, and carrying in turn one or more optional alkyl substituents of from about 1 to 3 carbon atoms. In a process for the application of the exterior gel coat to molded plastic substrates, including fiber reinforced substrates, the substrate is applied to said gel coat while it is in a tacky state of only partial cure so as to achieve a bonding between the substrate and the gel coat.

1 . A thermosettable in-mold exterior gel coat composition exhibiting low or no volatile organic content for use with molded plastic substrates, including fiber reinforced substrates, wherein said gel coat composition is composed of an ethynically unsaturated polyester resin and utilizing as a co-polymerizable reactive diluent therein an acrylate or methacrylate ester component having from 2 to 4 carbon atom alkyl substituent radicals depending thereon, coupled with a 5 to 10 carbon-atom-containing mono or dicyclic alkyl or alkenyl ester radical, and carrying in turn one or more optional alkyl substituents of from about 1 to 3 carbon atoms.  
     
     
         2 . A thermosettable in-mold exterior gel coat composition exhibiting low or no volatile organic content for use with molded plastic substrates, including fiber reinforced substrates, wherein said gel coat composition is composed of an ethynically unsaturated polyester resin and utilizing as a co-polymerizable reactive diluent therein an acrylated or a methacrylated isobornyl component.  
     
     
         3 . A thermosettable in-mold exterior gel coat composition exhibiting low or no volatile organic content for use with molded plastic substrates, including fiber reinforced substrates, wherein said gel coat composition is composed of an ethynically unsaturated polyester resin and utilizing as a co-polymerizable reactive diluent therein a methacrylated isobornyl component.  
     
     
         4 . The composition of  claim 1  wherein said component is present as a substantially monomeric material.  
     
     
         5 . The composition of  claim 1  wherein at least a portion of said component is present as a substantially low oligomeric material of from about 2 to about 5 monomeric units.  
     
     
         6 . A process for the application of an exterior gel coat to molded plastic substrates, including fiber reinforced substrates, wherein said gel coat composition is composed of an ethynically unsaturated polyester resin and utilizing as a co-polymerizable reactive diluent therein an acrylate or methacrylate ester component having from 2 to 4 carbon atom alkyl substituent radicals depending thereon, coupled with a 5 to 10 carbon-atom-containing mono or dicyclic alkyl or alkenyl ester radical, and carrying in turn one or more optional alkyl substituents of from about 1 to 3 carbon atoms, wherein said substrate is applied to said gel coat while it is in a tacky state of only partial cure so as to achieve a bonding between the substrate and the gel coat.